Download SPHS 4050, Neurological bases, PP 03c

PP 03c-Gross anatomy, in
more detail
Brainstem
• Structures:
– Midbrain
– Pons
– Medulla
Brainstem
• Functions:
– Genetically wired auto-control
mechanism called __________
system, for
• vital visceral functions such as ________
and ________
• With reticular projections form reticular
activating system, that regulates arousal
& consciousness, as they affect higher
cortical functions such as thought and
attention
– Connection of cortex to sensory and
motor areas of face and body
• Ascending somato-sensory tracts
• Descending motor tracts
• Synapses in the brainstem occur in the cranial
nerve nuclei (groups of cell bodies), which are
part of the pathways important for speech
and swallowing
Reticular projections
connect through
thalamus =
“gateway” to cortex
Midbrain
• Anatomy and functions:
– Tectum
• Superior colliculus - visual reflexes and
eye/head/balance coordination
• Inferior colliculus - audition
– Tegmentum
– Basis pedunculi includes substantia nigraParkinson’s disease
– Red nucleus (rubro-spinal pathway)
Pons
• Function:
– Regulation of sensorimotor and
cranial nerve functions
– Especially important for its
connections to the cerebellum
• Anatomy:
– Middle cerebellar peduncle
– Pontine tegmentum
– 4th ventricle
Medulla Oblongata
• Functions
•
– Modulation of sensorimotor and
cranial nerve activities and
– regulation of vital (cardiac,
swallowing, & respiratory) centers
part of ______________ system
Anatomy
– Descending motor (pyramidal) tract
– Ascending sensory tract
– Inferior olivary nucleus (hearing)
– Inferior cerebellar peduncle
– Sensory decussation (contralaterality)
– Pyramidal decussation
(contralaterality)
Cont’d
• Spinal Divisions (31 Pairs of Nerves)
– Cervical (n=8)
– Thoracic (n=12)
– Lumbar (n=5)
– Sacral (n=5)
– Coccygeal (n=1)
Cerebellum
• Function:
– Modification of cortical motor
functions (coordination)
• Coordination of skilled motor activity with inputs from
basal ganglia and cerebral cortex
•
– Maintenance of equilibrium, with
inputs from the vestibular system
Anatomy
– Surface of gray matter & medullary
core of white matter
– Hemispheres
– Lobes (anterior posterior &
floccular nodular)
– Cerebellar peduncles (superior,
middle, and inferior)
Cont’d
• Cerebellar Peduncles
– Connecting cerebellum with brainstem
• Input to Cerebellum
– Middle cerebellar peduncle- afferents from the
motor cortex
– Inferior cerebellar peduncle- afferents from
trunk/limbs & vestibular information to cerebellum
• Output from Cerebellum
– Superior cerebellar peduncle- corrective feedback to
opposite motor cortex, reticular formation & spinal
cord
Spinal Cord: Structure
• Link between brain & body
– Regulation of sensorimotor
reflexes and autonomic activities
– Foramen magnum- exit point
– Afferent sensory fibers, connect
to afferent white matter of
interneurons
– Efferent motor fibers, receive
connections from efferent white
matter of interneurons
Spinal Anatomy
• Internal Anatomy
– Gray & white matters
– Dorsal & ventral horns
– Sensory & motor nerve
fibers
• Spinal Nerves
– Dorsal & ventral rami
Spinal Distribution
• Dermatomal Representation
– Cutaneous body region
receiving its sensory
innervation from one
spinal nerve
• Myotomal Representation
– Muscles innervated by the
motor neurons of a single
spinal segment (indicated
in orange, in figure on
right)
Spinal nerves (PNS)
carry both sensory and
motor impulses
Think: Which nerves below are important for
communication, and which spinal nerves do they
emerge from?